Patent GB-590610-A (GB)
Title: Improvements in the treatment of textile materials
IPC: D01D10/00
Filed: 1944-10-16
Abstract: Textile fibres, filaments, yarns, tows, or fabrics, especially in the form of bulky masses such as wound packages, batts and felts are modified or conditioned by distributing throughout the entire body of the material a solution or dispersion of at least one component which undergoes chemical reaction during subsequent heating, and heating the material to cause the reaction and to remove the solvent or dispersing agent by subjecting the material to a high-frequency electrostatic or electromagnetic field.  The space surrounding the material may be maintained under a vacuum or pressure during the subjection to the electric field.  The conditioning agent, which may be used for crease-proofing, indurating, or improving the handle of the yarns or fibres, may be a single material which reacts with the fibres, or one which polymerises to produce an insoluble material, or may be a mixture of two or more components which react with each other, e.g. to produce a condensation product.  The solvent or dispersion medium may be removed at a relatively low temperature, and, after a definite moisture content is attained, the temperature raised for a short time to effect the desired reaction.  The fibres may be cellulosic, e.g. cotton or regenerated cellulose, protein such as casein or soya bean protein, and resinous materials such as acrylate resins and specified polyvinyl resins.  Materials which react with the fibres may be formaldehyde or an alum (for casein fibres), esterifying agents or quaternary ammonium compounds (for cellulosic fibres), and saponifying agents (for cellulose ester fibres).  Other treating materials are water-soluble partial condensation products of aldehydes with phenols, urea, or amines, for example melamine, a mixture of polyvinyl alcohol and butyraldehyde, a mixture of a protein such as casein, glue, or gelatine and a hardening agent such as formaldehyde or an alum, or a mixture of linseed or other drying oil with an oxidation accelerator such as lead or manganese oxide and a solvent.  The material may be treated in a continuous or batch process.  In examples: (1) a tow of freshly-precipitated and still wet viscose filaments is passed continuously through aqueous dimethylol urea, through squeeze rolls, and through a pair of U-shaped electrodes connected to opposite poles of an oscillator; (2) cakes of viscose rayon, prior to drying, are saturated with aqueous dimethylol urea, centrifuged, and subjected to a high-frequency field, a vacuum being maintained during the first, drying stage and the temperature being subsequently allowed to rise to cure the resin.  The Specification as open to inspection under Sect. 91 comprises also the treatment of fibrous materials with vapours, e.g. cellulose fabric with steam and formaldehyde; and heating merely to remove solvents, e.g. the drying of nylon yarn treated with an aqueous solution of partly hydrolized polyvinyl acetate, or of viscose rayon fabric treated with a dioxane solution of a chlorinated copolymer of vinyl acetate and vinyl chloride.  This subject-matter does not appear in the Specification as accepted.